The inventive subject matter relates to electrical apparatus and, more particularly, to electrical apparatus that install in enclosures with frictional electrical connections.
Electrical equipment, such as motor drives and starters, may include electrical assemblies, such as circuit breakers, contactors, and other switching devices that are configured to be removably installed in an enclosure. For example, a motor starter may employ a contactor assembly that is carried by a wheeled undercarriage that facilitates insertion of the contactor assembly into an enclosure. The contactor assembly may employ frictional electrical connections, such as spring loaded contacts or “stabs” that are designed to frictionally engage bus bars in the enclosure when the assembly is installed. Examples of such contactor assemblies are illustrated in a data sheet Motor Control (AMPGARD)-Medium Voltage, Sheet 10001, Eaton Corporation (November 2015).
Removal of such an assembly from an enclosure may require considerable force. In particular, the electrical connections may require significant disengagement force due to the number of connections (e.g., three input and three output phases) and the frictional forces generated between the contacts and the bus bars. Conventionally, personnel extracting such a contactor assembly from an enclosure may employ a pry bar to force movement of the contactor assembly and disengagement of the contacts.